CA1262320A - Explosive shock tube having lateral initiation properties - Google Patents
Explosive shock tube having lateral initiation propertiesInfo
- Publication number
- CA1262320A CA1262320A CA000471937A CA471937A CA1262320A CA 1262320 A CA1262320 A CA 1262320A CA 000471937 A CA000471937 A CA 000471937A CA 471937 A CA471937 A CA 471937A CA 1262320 A CA1262320 A CA 1262320A
- Authority
- CA
- Canada
- Prior art keywords
- tube
- slits
- energy
- shock tube
- shock
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
- F42D1/04—Arrangements for ignition
- F42D1/043—Connectors for detonating cords and ignition tubes, e.g. Nonel tubes
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
- C06C5/00—Fuses, e.g. fuse cords
- C06C5/04—Detonating fuses
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
Abstract "Explosive Shock Tube Having Lateral Initiation Properties"
A modified explosive shock tube is provided which has a lateral energy output and hence may be used as a trunk line in a non-electric blasting network. The modified shock tube comprises a hollow, flexible plastic tube having a layer of energy-producing material on its inner surface and also having at intervals along its length, cuts or slits which penetrate the tube wall. The area of the slits has an overcovering of a waterproof material. When energized, the tube will burst at the area of the slits to release energy in a direction lateral to the tube axis.
A modified explosive shock tube is provided which has a lateral energy output and hence may be used as a trunk line in a non-electric blasting network. The modified shock tube comprises a hollow, flexible plastic tube having a layer of energy-producing material on its inner surface and also having at intervals along its length, cuts or slits which penetrate the tube wall. The area of the slits has an overcovering of a waterproof material. When energized, the tube will burst at the area of the slits to release energy in a direction lateral to the tube axis.
Description
q3~
The present invention relates to low energy explosive shock tubing of the NONEL (Reg. TM) type. In particular, the invention relates to an explosive shock tube which is capable o the lateral initiation of a second, attached length of shock tube.
Explosive shock tubing as disclosed in Canadian Patent No. 878,056 granted August 10, 1971 is now widely known and used inthe blasting art. This shock tubing or detonating fuse consists of small diameter, for example, 3 millimeters outside diameter tubing of a pliable plastic, such as, polyvinyl chloride, polyethylene, SURLYN (Reg. TM) or the like having an inner diameter of about 1.3 millimeters. The inner walls of the tubing has adhered thereto a thin layer of powdered explosive or reactive material, such as PETN
(pentaerythritol tetranitrate), HMX (cyclotetramethalene-tetranitramine) or powdered metal mixtures with these.
When initiated at one end by means of an appropriate device, such as a detonating cap, a percussion or impact wave is propagated within and along the tubing to activate a blasting cap attached at the remote end of the tubing. When initiated, substantially all of the percussion wave energy is confined within the tube and little or no damage to the tube wall occurs. Indeed, it has been stated that the absence of any lateral energy allows an initiated shock tube to be held in the hand without great risk o~ injury. Explosive shock tubing may be employed in most instances as a replacement for conventional detonating cord in non-electric blasting and has the advantage of low noise, safe handling and low cost.
'~
The present invention relates to low energy explosive shock tubing of the NONEL (Reg. TM) type. In particular, the invention relates to an explosive shock tube which is capable o the lateral initiation of a second, attached length of shock tube.
Explosive shock tubing as disclosed in Canadian Patent No. 878,056 granted August 10, 1971 is now widely known and used inthe blasting art. This shock tubing or detonating fuse consists of small diameter, for example, 3 millimeters outside diameter tubing of a pliable plastic, such as, polyvinyl chloride, polyethylene, SURLYN (Reg. TM) or the like having an inner diameter of about 1.3 millimeters. The inner walls of the tubing has adhered thereto a thin layer of powdered explosive or reactive material, such as PETN
(pentaerythritol tetranitrate), HMX (cyclotetramethalene-tetranitramine) or powdered metal mixtures with these.
When initiated at one end by means of an appropriate device, such as a detonating cap, a percussion or impact wave is propagated within and along the tubing to activate a blasting cap attached at the remote end of the tubing. When initiated, substantially all of the percussion wave energy is confined within the tube and little or no damage to the tube wall occurs. Indeed, it has been stated that the absence of any lateral energy allows an initiated shock tube to be held in the hand without great risk o~ injury. Explosive shock tubing may be employed in most instances as a replacement for conventional detonating cord in non-electric blasting and has the advantage of low noise, safe handling and low cost.
'~
- 2 - C-I-L 675 While the characteristic of lack of sideways or lateral bursting of conventional shock tube is advantageous from a safety viewpoint, the absence of the characteristic of lateral energy output preclud~s the use of shock tubing as a trunk line in non-electric blasting networks. Shock tubing heretofore has been limited for use as branch lines which are initiated by attachment to conventional, solid-core detonating fuse trunk line. Such conventional detonating fuse or detonating cord has a strong lateral energy output which is capable of initiating any properly attached shock tube branch lines.
In the preparation of non-electric, multiple-change blasting networks, a conventional detonating cord trunk line is laid along the ground surface or blasting face surface with the attached shock tube branch lines passing into the boreholes to set off the cap/charge combinations within the borehole. A large noise factor is associated with such circuits from the detonation of the surface trunk line which noise is objectionable, particularly on construction projects in built-up areas. There is a need, therefore, for a substantially noiseless, cost-effective alternative to detonating cord trunk line.
SUMMA _ OF THE INVENTION
A modified explosive shock tube is provided which is capable of lateral initiation of an attached length of a second shock tube, which modified shock tube may be employed as a substantially noiseless trunk line in a non-electric blasting network.
The modified shock tube of the invention comprises a hollow, elongated flexible tube, the inner surface of which has a thin layer of powdered, energy-producing material distributed thereon. The shock tube has, at periodic intervals along its length, areas which are capable of
In the preparation of non-electric, multiple-change blasting networks, a conventional detonating cord trunk line is laid along the ground surface or blasting face surface with the attached shock tube branch lines passing into the boreholes to set off the cap/charge combinations within the borehole. A large noise factor is associated with such circuits from the detonation of the surface trunk line which noise is objectionable, particularly on construction projects in built-up areas. There is a need, therefore, for a substantially noiseless, cost-effective alternative to detonating cord trunk line.
SUMMA _ OF THE INVENTION
A modified explosive shock tube is provided which is capable of lateral initiation of an attached length of a second shock tube, which modified shock tube may be employed as a substantially noiseless trunk line in a non-electric blasting network.
The modified shock tube of the invention comprises a hollow, elongated flexible tube, the inner surface of which has a thin layer of powdered, energy-producing material distributed thereon. The shock tube has, at periodic intervals along its length, areas which are capable of
3~
bursting to release energy laterally to the axis of the tube upon initiation of the energy-producing material within the tube. In particuIar, the invention comprises an explosive shock tube, the walls of which are perforated at intervals along its length by means of elongated cuts or slits, the cuts or slits being protected with a -thin outer layer or covering of waterproofing material. When the shock tube is initiated, the area of the slits will open and energy from the deflegrating material within the tube will be delivered through the opened slits at right-angles to the tube axis. This lateral energy is used to initiate a second length of shock tube the end of which second tube is positioned in alignment with the slits.
A more detailed explanation of the invention is provided in the following description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a partly cut-away perspective view of the shock tube of the invention showing the slit areas;
Figure 2 is a cross-section of the shock tube of Figure 1 taken along the line A-A; and Figure 3 shows a partly cut-away perspective view of a connection between the shock tube of the invention as a trunk line and a conventional shock tube as a branch line.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figures 1 and 2, there is shown a shock tube generally designated 1, which contains an inner core hollow tube of plastic material 2. The inner wall of tube 2 has adhered thereto a thin layer of powdered explosive or reactive material 3. A thin overcovering material 4 is shown enveloping tube 2. Tube 2, as shown in the cut away section, contains a series of cuts or slits 5 which penetrate the tube walls. In the Figures, the thickness of overcovering 4 as shown is exaggerated for clarity.
3~
bursting to release energy laterally to the axis of the tube upon initiation of the energy-producing material within the tube. In particuIar, the invention comprises an explosive shock tube, the walls of which are perforated at intervals along its length by means of elongated cuts or slits, the cuts or slits being protected with a -thin outer layer or covering of waterproofing material. When the shock tube is initiated, the area of the slits will open and energy from the deflegrating material within the tube will be delivered through the opened slits at right-angles to the tube axis. This lateral energy is used to initiate a second length of shock tube the end of which second tube is positioned in alignment with the slits.
A more detailed explanation of the invention is provided in the following description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a partly cut-away perspective view of the shock tube of the invention showing the slit areas;
Figure 2 is a cross-section of the shock tube of Figure 1 taken along the line A-A; and Figure 3 shows a partly cut-away perspective view of a connection between the shock tube of the invention as a trunk line and a conventional shock tube as a branch line.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figures 1 and 2, there is shown a shock tube generally designated 1, which contains an inner core hollow tube of plastic material 2. The inner wall of tube 2 has adhered thereto a thin layer of powdered explosive or reactive material 3. A thin overcovering material 4 is shown enveloping tube 2. Tube 2, as shown in the cut away section, contains a series of cuts or slits 5 which penetrate the tube walls. In the Figures, the thickness of overcovering 4 as shown is exaggerated for clarity.
3~
- 4 - C-I-L 675 Tube l is manufactured by first preparing a shock tube in a conventional manner, that is, plastic tubing 2 is extruded through a die with the simultaneous application of powdered explosive material to the inner wall thereof.
The plastic of tubing 2 is preferably made from SU~,YN, a salt-containing polyethylene ionomer, although any flexible plastic having good properties of adherence for the powdered explosive material can be used. The size of tube 2 is typically about 3 mm. outside diameter and 1.3 mm. lnside diameter. After extrusion, tube 2 is passed lengthwise through a reciprocating cutter device where a series of slits
The plastic of tubing 2 is preferably made from SU~,YN, a salt-containing polyethylene ionomer, although any flexible plastic having good properties of adherence for the powdered explosive material can be used. The size of tube 2 is typically about 3 mm. outside diameter and 1.3 mm. lnside diameter. After extrusion, tube 2 is passed lengthwise through a reciprocating cutter device where a series of slits
5 from about .5-l cm. in length are made, preferably two to four in number, through the tube walls and spaced equally around the circumference of tube 2. Slits 5 may be made at any chosen linear interval along tube 2. After being slit, tube 2 is passed through a second circular die where a thin, external layer or coating of flexible waterproofing material 4 is bonded to the outer surface of tube 2. Alternatively, a spray coating of waterproofing material may be applied or a short length of adhesive tape, for example, vinyl tape can be applied over the area of the slits. A suitable water-proofing material 4 is, for example, a polyethylene/ethylvinyl acetate blend. To assist in locating the position oE the slits 5 in the finished tube 1, the slit area of tube 2 may be coloured with an ink or dye prior to overcoating with waterproof layer 4.
With reference to Figure 3, there is shown a generally T-shaped connector device lO mounted on or around trunk line shock tube l. Connector 10 may comprise any configuration which permits the location of an end 11 of branch line shock tube 12 close to the slits 5 in trunk line 1. Connector 10, as shown, is typical of several known T-shaped connectors used in assembling blasting fuse circuits. In the depiction shown in Figure 3, connector lO which is hinged and sized to fit tightly around trunk line 1, is mounted so that its cen-tral area is adjacent to slits 5 in trunk line 1. Le~
portion 13 of connector 10 is si~ed to receive in tight-gripping relationship the end of a shock tube branch line 12 which is inserted into leg portion 13 until tube end 11 is close to or abutting slits 5, When trunk line 1 is initiated at a remote end (not shown), the energy pulse within tube 1 opens the slits 5 and bursts the o~ercoating layer 4 to initiate the energetic material 14 within branch line 12.
A similar trunk-to-branch connection can be made at each slit location alongtrunk line 1, each branch line leading to a separate explosive charge in a blasting network.
EXAMPLE I
A NONEL shock tube containing 25 mg/m of a mixture comprising 8~ powdered aluminium and 92% powdered HMX
explosive was prepared for us~ as a trunk line in a 200 meter length. At one meter intervals along its length, two diametrically opposite slits .6 cmO in length were made in the shock tube trunk line. The location of each slit was indicated with an inked mark. The slit NONEL was overcoated by an extrusion process with a clear polyethylene/ethylvinyl acetate sleeve 0.2 mm. in thickness. Fifty standard NONEL
receptor tube lengths were positioned adjacent the marked slits in the trunk line using the connector shown in Figure 3 and the trunk line was initiated at one end by means of a NONEL-type initiator. All 50 receptor tube lengths were initiated without failure. In a similar test using un-slit NONEL having the same explosive content as the trunk line, no branch line initiation occurred.
EXAMPLE II
The test described in Example I was repeated at temperatures of -40C employing ten branch line connections.
No failures occurred.
- ~ - C-I-L ~75 It has been observed that the material employed as the overcovering or waterproofing material 4 should be chosen so as to avoid fragmentation during initiation since small fragments of material could cause blockage of the end of the receptor or branch line tune and interfere with energy transfer between trunk line and branch line. It will be obvious to those skilled in the art, that the open end of the receptor branch line must be kept dry to ensure initiation.
It will also be obvious that the amount of energetic material employed on the inner wall of tube 2 must be sufficient to provide energy adequate to open slits 5 and to rupture overcovering 4. The amount of energetic material used will depend on the length of slit 5, flexibility of the material of tube 2 and the thickness and resistance to rupture of the overcovering material 4.
With reference to Figure 3, there is shown a generally T-shaped connector device lO mounted on or around trunk line shock tube l. Connector 10 may comprise any configuration which permits the location of an end 11 of branch line shock tube 12 close to the slits 5 in trunk line 1. Connector 10, as shown, is typical of several known T-shaped connectors used in assembling blasting fuse circuits. In the depiction shown in Figure 3, connector lO which is hinged and sized to fit tightly around trunk line 1, is mounted so that its cen-tral area is adjacent to slits 5 in trunk line 1. Le~
portion 13 of connector 10 is si~ed to receive in tight-gripping relationship the end of a shock tube branch line 12 which is inserted into leg portion 13 until tube end 11 is close to or abutting slits 5, When trunk line 1 is initiated at a remote end (not shown), the energy pulse within tube 1 opens the slits 5 and bursts the o~ercoating layer 4 to initiate the energetic material 14 within branch line 12.
A similar trunk-to-branch connection can be made at each slit location alongtrunk line 1, each branch line leading to a separate explosive charge in a blasting network.
EXAMPLE I
A NONEL shock tube containing 25 mg/m of a mixture comprising 8~ powdered aluminium and 92% powdered HMX
explosive was prepared for us~ as a trunk line in a 200 meter length. At one meter intervals along its length, two diametrically opposite slits .6 cmO in length were made in the shock tube trunk line. The location of each slit was indicated with an inked mark. The slit NONEL was overcoated by an extrusion process with a clear polyethylene/ethylvinyl acetate sleeve 0.2 mm. in thickness. Fifty standard NONEL
receptor tube lengths were positioned adjacent the marked slits in the trunk line using the connector shown in Figure 3 and the trunk line was initiated at one end by means of a NONEL-type initiator. All 50 receptor tube lengths were initiated without failure. In a similar test using un-slit NONEL having the same explosive content as the trunk line, no branch line initiation occurred.
EXAMPLE II
The test described in Example I was repeated at temperatures of -40C employing ten branch line connections.
No failures occurred.
- ~ - C-I-L ~75 It has been observed that the material employed as the overcovering or waterproofing material 4 should be chosen so as to avoid fragmentation during initiation since small fragments of material could cause blockage of the end of the receptor or branch line tune and interfere with energy transfer between trunk line and branch line. It will be obvious to those skilled in the art, that the open end of the receptor branch line must be kept dry to ensure initiation.
It will also be obvious that the amount of energetic material employed on the inner wall of tube 2 must be sufficient to provide energy adequate to open slits 5 and to rupture overcovering 4. The amount of energetic material used will depend on the length of slit 5, flexibility of the material of tube 2 and the thickness and resistance to rupture of the overcovering material 4.
Claims (3)
1. A modified low energy explosive shock tube having lateral directional energy output comprising a hollow elongated flexible tube the inner surface of which has a thin layer of powdered energy-producing material distributed thereon, the said tube having at periodic intervals along its length one or more slits which penetrate the said hollow tube to release energy laterally to the axis of said tube upon ignition of said energy-producing material, the said slits being sealed by a thin external rupturable overcovering.
2. A shock tube as claimed in Claim 1, wherein the thin overcovering comprises a polyethylene/ethylvinyl acetate sleeve.
3. A shock tube as claimed in Claim 1, wherein the thin overcovering comprises an adhered vinyl film tape.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000471937A CA1262320A (en) | 1985-01-11 | 1985-01-11 | Explosive shock tube having lateral initiation properties |
| AU52106/86A AU578338B2 (en) | 1985-01-11 | 1986-01-08 | Shock tubing |
| ZA86166A ZA86166B (en) | 1985-01-11 | 1986-01-09 | Explosive shock tube having lateral initiation properties |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000471937A CA1262320A (en) | 1985-01-11 | 1985-01-11 | Explosive shock tube having lateral initiation properties |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1262320A true CA1262320A (en) | 1989-10-17 |
Family
ID=4129560
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000471937A Expired CA1262320A (en) | 1985-01-11 | 1985-01-11 | Explosive shock tube having lateral initiation properties |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU578338B2 (en) |
| CA (1) | CA1262320A (en) |
| ZA (1) | ZA86166B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2836786A4 (en) * | 2012-04-13 | 2015-09-30 | C 2 Innovations Inc | Line charge |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3712222A (en) * | 1970-03-12 | 1973-01-23 | Brunswick Corp | Pyrotechnic fuse |
-
1985
- 1985-01-11 CA CA000471937A patent/CA1262320A/en not_active Expired
-
1986
- 1986-01-08 AU AU52106/86A patent/AU578338B2/en not_active Ceased
- 1986-01-09 ZA ZA86166A patent/ZA86166B/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2836786A4 (en) * | 2012-04-13 | 2015-09-30 | C 2 Innovations Inc | Line charge |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA86166B (en) | 1986-09-24 |
| AU578338B2 (en) | 1988-10-20 |
| AU5210686A (en) | 1986-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4699059A (en) | Explosive shock tube having lateral initiation properties | |
| CA1057577A (en) | Non-electric double delay borehole downline unit for blasting operations | |
| US6006671A (en) | Hybrid shock tube/LEDC system for initiating explosives | |
| US4757764A (en) | Nonelectric blasting initiation signal control system, method and transmission device therefor | |
| US5365851A (en) | Initiator device | |
| US4481884A (en) | Field-connected explosive booster for initiating low-energy explosive connecting cords | |
| US5747722A (en) | Detonators having multiple-line input leads | |
| US5417162A (en) | Detonation coupling device | |
| US3987733A (en) | Millisecond delay surface connector | |
| US4378844A (en) | Explosive cutting system | |
| US3878785A (en) | Propagation device and initiation system for low energy fuses | |
| RU2000107782A (en) | SENDING SIGNAL FIRE WIRE CORD AND METHOD FOR ITS MANUFACTURE | |
| WO1999010300A2 (en) | Signal transmission fuse and method of making the same | |
| GB2054108A (en) | Energy transmission device | |
| US7162957B2 (en) | Redundant signal transmission system and development method | |
| CA1064322A (en) | Elongated, flexible detonating device | |
| US4799428A (en) | Explosive primer unit for instantaneous initiation by low-energy detonating cord | |
| US4023493A (en) | Fireline detonator | |
| US5012741A (en) | Initiator for a transmission tube | |
| US5763816A (en) | Explosive primer | |
| CA1262320A (en) | Explosive shock tube having lateral initiation properties | |
| CA2259612C (en) | Fissile shock tube and method of making the same | |
| US4716831A (en) | Detonating cord connector | |
| US5689083A (en) | Obturating initiation fitting | |
| CA2203147C (en) | Alternate signal path isolation member and non-electric detonator cap including the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |